Pasteurization involves an application of mild heat for a specified time to a liquid food or beverage to enhance its keeping properties, and to destroy any harmful microorganisms present. For milk, the times and temperatures employed for such pasteurization are based upon the thermal tolerance of Mycobacterium tuberculosis, one of the most heat resistant of non-spore-forming pathogens. Vegetative cells of most bacteria are generally eliminated by heat treatment, while endospores are unaffected.
In the food preparation industry, pasteurization is accomplished by placing a batch of liquid food or beverage containers (which generally includes several sealed bottles) into an oven or heated area at a particular temperature for a particular period of time based on the characteristics of the liquid food or beverage. By heating the liquid food or beverage, its keeping properties are enhanced, and harmful microorganisms are destroyed therein. Once the batch of liquid food or beverage is removed from the oven or heated area, a bottle of the liquid food or beverage is tested to determine if it has been properly pasteurized. Many times, the liquid inside the test bottle is properly pasteurized. At times, however, the liquid inside the test bottle may be overly pasteurized causing the liquid to be burnt or under pasteurized. Thus, the keeping properties may be underdeveloped, and/or harmful microorganisms are possibly allowed to survive. Over-pasteurization or under-pasteurization can be the product of inadequate modeling of the thermodynamic properties of the liquid food or beverage, unexpected or uneven heating of the oven or heating area, unexpected environmental conditions, variations in the temperature of the liquid food or beverage prior to the pasteurization process, or other manufacturing variants. If the liquid food or beverage inside the test bottle is over pasteurized or under pasteurized, the entire batch of liquid food or beverage must be destroyed.
Certain publications relate to systems and methods for measuring an environmental condition. For example, the U.S. Pat. No. 4,576,781 issued to Duncombe et al. describes a method for detecting a threshold temperature by providing a sensor which includes a magnet inside a ferromagnetic shield that has a lower Curie point than that of the magnet. Below the threshold temperature, the sensor is magnetically characterless. Above the threshold is reached, the sensor displays a magnetic character which is detected at a solid state magnetometer. The sensor can be located inside a sealed containment vessel, and the solid state magnetometer can be located outside the vessel.
U.S. Pat. No. 5,255,977 issued to Eimer et al. (the Eimer Patent) describes a method and apparatus for monitoring the heat transfer and therefore the efficiency of a condenser. A temperature probe is used to measure the temperature within an outlet chamber, and transmit the measured temperature to evaluating means. The temperature probe and the evaluating means are connected by lines. The Eimer Patent also discloses that it is possible to provide wireless transmission from the temperature probe to the evaluating means.
U.S. Pat. No. 6,208,253 issued to Fletcher et al. describes an apparatus and method for temperature sensing through observable, temperature dependent effects on an interrogating magnetic field facilitated by a sensing module. The sensing module has a signal element that interacts with the interrogation field to product a remotely readable magnetic response, and disposed proximate to the signal element. In a three-layer sensor implementation, a signal layer, a modulation layer and a bias layer are provided. The shunting effect of the modulation layer on the bias layer generally occurs more gradually than the demagnetization of the bias layer alone in a two-layer implementation. It is possible to fabricate a three-layer sensor that is operative over varying temperature ranges through a selection of modulation layer compositions having appropriate Curie temperatures. Additionally, the three-layer implementation has a reversible harmonic type, such that the three-layer temperature sensor continues to function even after the temperature of the modulation layer of the sensor falls below the Curie temperature of the modulation layer of the sensor, i.e., after the temperature has been above the Curie temperature for a period of time.
U.S. Pat. No. 6,369,894 issued to Rasimas et al. describes a modular fluorometer and a method of using the same to control an industrial water system. The modular fluorometer can be used with water from any water system, including with water used in industrial water systems (e.g., indirect contact cooling and heating water, such as pasteurization water). The modular fluorometer may accommodate a temperature sensor. Also, it is possible to use a wireless communication protocol between the modular fluorometer and a controller.
International Publication Number WO 02/27276 by Tietsworth et al. describes a flow meter and method for determining the corrected flow rate of a liquid falling into a predetermined class of liquids based on its viscosity and density. The flow meter includes a temperature sensor, which measures the temperature of the syrup and sends the measured temperature to a microprocessor. The flow meter can also include a wireless communication system.
However, none of the above publications describe a system and method which effectively and continuously monitors environmental conditions.